Rough idle with forced induction

jwick

Just throwing ideas out. Partially for my understanding and partially to see if any trigger some light bulb in your mind that leads us to a solution. I could be completely off but stick with me. So NA it's pulling metered air in from the intake (post-MAF). I would guess the ECU is expecting a certain amount of air to be removed from what it's metering, where in reality (vented) the crankcase is pulling in as much unmetered air as it wants. There is no adjustment for that air not being removed and when you come off throttle it hiccups because it's getting more air than it expects leading to the lean condition. Which is what we see happening.

But let me throw an additional monkey wrench. The GTM kit ties that secondary in pre-MAF, so it has to be something different or in addition to what I stated above or there is something in the tuning that can correct for that.

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'10 G37T 6MT Graphite/Graphite - BP - G37T Build

Mitco39

You could be right, as the car switches from open loop to close loop it could cause a hiccup until it stabilizes itself. Easy way to try and see if this is causing it is to pull both lines and plug the ports in the intake manifold and idle the car and see what happens. You could just vicegrip the lines to and let the secondary system do all the venting. I am going to try that this weekend and see what the car does.

Is that secondary drawn in pre-turbo? It could be that there is enough vac pre turbo to keep the air being drawn through that system to minimum. But your right the same principle applies in this case as well. Its a head scratcher for sure. Ill try and get some time tonight with the car.

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2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

nomodsjk

Again I made NO reference to who was trying to solve the problem just that someone else had the same problem, someone with more experience than me. No reason to get worked up over something that wasn't said.

Mitco39

Its all good. No worries here.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

jwick

Ran a couple logs when I got home. Do we have a way transfer/upload them?

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'10 G37T 6MT Graphite/Graphite - BP - G37T Build

GaleForce

Dropbox?

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jwick

Anybody got one?

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'10 G37T 6MT Graphite/Graphite - BP - G37T Build

GaleForce

It's all good. Just a bit of ball busting on the interwebz.

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Mitco39

Dropbox or google drive works great.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

Mitco39

I think this solved it for me. The idle is damn near perfect. Dont mind the wideband I am convinced its not 100 percent accurate. The cars O2s are much closer to stoic.

Also the engine doesnt sound that ticky in person, the phone camera picks up that frequency more than others. It also comes down to idle nice and smooth.

I am just going to have to pick up a oil catch can and vent to atm and that should do it. Once this is done there is really no reason to keep those two filters either, it can all be deleted and routed through the catchcan.

Let me know what you guys think.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

jwick

Have you driven it? Is the hiccup sti 'll there or did it fix that too?

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'10 G37T 6MT Graphite/Graphite - BP - G37T Build

Mitco39

I havent drove it because I dont want oil to get all over my engine, that will have to wait until I get a oil catch can. I reved it up a few times like that and it settled down perfectly. But your right, it would have to be road tested to confirm 100 percent.

I could hear the idle instantly change when I plugged back in the stock lines.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

jwick

So pumped for the final results Mitch. You ever in Texas, tab is on me!

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'10 G37T 6MT Graphite/Graphite - BP - G37T Build

Mitco39

Ill order a catch can next week and give it a shot. Anyone run one or have any suggestions as which one is the best?

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

GaleForce

I was also wondering about blipping the throttle and seeing what happens with the idle. It does seem nice and smooth in your video though.

Oil catch can,

Radium Oil Catch Cans

Mr.Squeeze has said he was going with one of these, I'm not sure if he received his though,

Saikou Michi Co. 2013

Here's another,

Ultimate Oil Catch Can

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